Preheat oven to 350 degrees. You can use either a 13X9 pan or two 9" cake pans for this, spray sides of baking dish(es) with cooking spray.,Drain pineapple, reserving all juice. Press it down into the strainer to remove excess juice in the pineapple. Measure out 3/4 cup of juice and discard the remaining juice or save for other purpose.,Cut butter into pieces and place into baking dish(es), sprinkle brown sugar on top of butter - divide both butter & brown sugar into halves if you are making it in two pans rather than one.,Place in oven while preheating until butter melts completely, then remove from oven, stir in the drained crushed pineapple. Set aside.,In a bowl mix together eggs, oil, rum and the 3/4 of pineapple juice saved from the can until well blended.,______,Pour evenly over the pineapple, butter, sugar mix in baking dish.,Bake for 30-36 minutes, test for doneness with toothpick.